The invention relates to a method for preparing the supply of electric power to a vehicle having a supply device, in particular an electric or a hybrid vehicle, with a supply apparatus supplying at least one supply voltage, wherein the vehicle and the supply apparatus are constructed separate from one another and can be releasably connected by a plug contact between the supply device of vehicle and the supply apparatus.
To rapidly supply an electrical or a hybrid vehicle with electrical energy, for example to rapidly charge an energy storage device of the vehicle, for example a battery, rapid delivery devices, so-called charging devices or rapid charging devices exist which are mostly configured as a charging station.
For example, conventional DC rapid charging stations have an output voltage range of 0 to 1500V DC, i.e. they are able to provide charging voltages between 0 and 1500V as DC voltage. For charging a battery of an electric vehicle, the electric vehicle and the DC rapid charging station are electrically connected together, for example, via a plug contact. FIG. 1 shows schematically such electrical connection or arrangement.
The DC rapid charging station 1 has a plug 2 connected to an AC/DC converter 3 and a PLC-component 4. The AC/DC converter 3 is in turn connected to a mains connection N.
The electric vehicle 5 includes a charging socket 6 cooperating with the plug 2, wherein the charging socket 6 is connected via HV lines HV+ and HV− (HV=high voltage) with a HV-plug device 7. The HV-plug device 7 is connected via circuit breakers K1 and K2 to the battery 8 to be charged. Furthermore, the charging socket 6 is connected with a PLC-component 9 of the vehicle. As an additional hardware-line, the so-called PRX-line 10 or proximity-line is connected on the vehicle side.
For charging the battery 8, the electric vehicle 5 notifies the battery 8 of vehicle 5 during an initialization phase of the DC charging process via power-line communication (PLC=power line communication) of the DC rapid charging station 1 about the maximum permissible charging voltage and the target voltage, i.e. the voltage level to be attained after charging is complete. The DC rapid charging station 1 then sets the desired charging voltage for the vehicle 5 accordingly. The vehicle 5 recognizes or measures the applied charging voltage with a voltmeter V1 and closes the vehicle-side circuit breakers K1 and K2, when the applied voltage corresponds to the requested charging voltage.
Disadvantageously, when communicating via PLC between a charging station or a supply device and a vehicle, the communication is not classified as safety-relevant. Errors in the communication between the charging station and the vehicle or errors in the charging station itself can cause the charging station to output or apply to the vehicle an exceedingly high charging voltage, for example 1500 V, although a lower charging voltage has been requested.
Therefore, the components of the vehicle 5 used for charging the battery 8 must be designed for safety reasons for a voltage of 1500V. However, components used in vehicles typically do not have this dielectric strength. The typical voltage range for a battery 8 is maximally 500V. The vehicle-side HV lines HV+ and HV− are typically designed for a voltage range of maximally 600V. The vehicle-side circuit breakers K1 and K2 as well as the vehicle-side HV-plug device 7 are typically designed for a voltage range of maximally 850V.
Designing the aforementioned components for maximally 1500V not only increases the costs and the weight of the vehicle, but a corresponding installation space in the vehicle for the corresponding voluminous components is also needed.
DE 10 2009 025 303 A1 describes a method for communicating with an electric vehicle, including generating a first predetermined DC level on a pilot conductor, identifying the existence an electrical connection with an electric vehicle by measuring a second predetermined DC level on the pilot conductor, emitting a trigger signal on the pilot conductor, measuring a vehicle identification signal on the pilot conductor and unblocking the power supply on a power conductor.
U.S. Pat. No. 5,548,200 discloses a charging station as well as a method for charging a battery of a vehicle, wherein the charging power can be supplied to the battery of electric vehicle regardless of the type of the charging controller installed in the vehicle and associated with the electric vehicle battery.